EXCLUSIVE: Kendrick Sampson (The Vampire Diaries, Gracepoint) has signed on for a substantive recurring role in the upcoming season of ABC’s How To Get Away With Murder. Details are being kept under wraps, but we’re told Sampson’s character will be introduced in the second season premiere on September 24. How To Get Away With Murder, created/exec produced by Pete Nowalk and executive produced by Shonda Rhimes, part of ABC’s Shondaland Thursday night, was last fall’s…